Scheduling trucks in local depots for door-to-door delivery services

A scheduling method is suggested for trucks delivering and picking up freight between branch offices and a regional depot in door-to-door delivery services. As the objective functions, different levels of customer service resulting from different timing of deliveries and pickups to/from branch offices are considered as well as the travel cost of trucks. Useful properties of the optimal timing of deliveries and pickups are derived to reduce the size of the search space significantly. Numerical experiments were conducted to evaluate various algorithms to solve the problem.